Engineering sorghum for higher 4-hydroxybenzoic acid content

Enhanced microbial production of protocatechuate from engineered sorghum using an integrated feedstock-to-product conversion technology

“…Recently, the bioenergy crop sorghum was engineered to overproduce and accumulate 4HBA, the predicted precursor to PCA in the R. toruloides p -coumaric acid consumption pathway. 37 This engineered feedstock provides an opportunity to obtain 4HBA-enriched hydrolysates for fermentation with the strain RS Δ12623 to produce PCA. A proven method for generating sugar-rich hydrolysates from sorghum is an ionic liquid-based ([Ch][Lys]) deconstruction process performing thermochemical pretreatment and enzymatic saccharification in the same vessel.…”

“…In the case of 4HBA sorghum, this aromatic compound is expected to be present in extractives in the form of glucose conjugates (presumably stored in vacuoles) and ester-bound to the cell wall. 37 Here we investigate the impact that 4HBA-enriched biomass may have on the composition of hydrolysates, residual lignin-containing solids, and the fermentation capabilities of R. toruloides , when subjected to this [Ch][Lys] conversion process. A scheme of the complete process is presented in Fig.…”

“…The engineered 4HBA overproducing sorghum (line Eng-2) used in this work has been previously described. 37 Engineered plants and wild-type segregant control (variety BTx430) in the T3 generation were cultivated at the University of California Davis Plant Sciences Research Farm in 2021. Growth conditions have been previously documented.…”

“…Growth conditions have been previously documented. 37 For each genotype, plants from an entire four-row plot (3 × 6 m) were harvested without their panicles using a Wintersteiger Cibus forage chopper (Wintersteiger, Salt Lake City, UT) and dried down in the field. Dried chopped biomass was further milled using a Model 4 Wiley Mill equipped with a 2 mm screen mesh (Thomas Scientific, Swedesboro, NJ).…”

Sustainable production of 2,3,5,6-Tetramethylpyrazine at high titer in engineeredCorynebacterium glutamicumusing statistical design of experiments

“…CGXII minimal medium was supplemented with hydrolysates obtained from sorghum biomass to test the ability of the engineered high TMP producing strain to utilize real world carbon streams treated with ionic liquids. Sorghum biomass (stems and leaves without panicles) from field-grown wild-type and genetically engineered plants that accumulate high amounts of 4-hydroxybenzoic acid (4-HBA) was obtained as previously described (34). Moreover, ensiled sorghum biomass was obtained from a commercial silage pit on a dairy farm in the southern part of the San Joaquin Valley, California.…”